statistics: fix data race in HandleUpdateStats (#33260)
statistics: fix data race in HandleUpdateStats (#33260)

ref pingcap/tidb#32867, ref pingcap/tidb#33001, close pingcap/tidb#33108
pingcap/tidb,kyle-wang/tidb,pingcap/tidb,kyle-wang/tidb,kyle-wang/tidb,c4pt0r/tidb,c4pt0r/tidb,kyle-wang/tidb,ngaut/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,pingcap/tidb,c4pt0r/tidb,ngaut/tidb,ngaut/tidb,pingcap/tidb,pingcap/tidb,ngaut/tidb,ngaut/tidb,c4pt0r/tidb,kyle-wang/tidb,c4pt0r/tidb,ngaut/tidb